Synthesis and Characterization of μ₃-η²,η²,η²-C₆₀ Trirhenium Hydrido Cluster Complexes

Abstract

The reaction of C 60 with Re 3 (µ-H) 3 (CO) 11 (NCMe) in refluxing chlorobenzene produces Re 3 (µ-H) 3 (CO) 9 (µ 3 -η 2 ,η 2 ,η 2 -C 60 ) (1) in 50% yield. Initial decarbonylation of 1 with Me 3 NO/ MeCN followed by reaction with PPh 3 in boiling chlorobenzene affords Re 3 (µ-H) 3 (CO) 8 (PPh 3 )-(µ 3 -η 2 ,η 2 ,η 2 -C 60 ) (2) in a low yield (26%). Treatment of 1 with PhCH 2 NdPPh 3 at room temperature gives a benzyl isocyanide substituted product Re 3 (µ-H) 3 (CO) 8 (CNCH 2 Ph)(µ 3η 2 ,η 2 ,η 2 -C 60 ) (3) in 53% yield. Compounds 1, 2, and 3 have been isolated as crystalline solids and characterized by spectroscopic (infrared, mass, 1 H, 31 P, and 13 C NMR) and analytical data. The structure of 3 has been determined by a single-crystal X-ray diffraction study. The C 60 ligand is coordinated to the trirhenium triangle in a µ 3 -η 2 ,η 2 ,η 2 bonding mode, and the benzyl isocyanide ligand occupies an axial position of a rhenium atom. Electrochemical properties of 1 and 2 have been studied by cyclic voltammetry (CV) in chlorobenzene (CB) solutions. The general features of CV curves have revealed four reversible redox couples for 1 and 2 in the CB potential window. The CV results suggest that a C 60 -mediated electron transfer to the trirhenium center takes place in 1 2species for 1 and 2 3for 2.

Syntheses, Characterisation and Electrochemical Properties of C70-metal Cluster Complexes

“…Furthermore, the IR spectra of 3 is similar to that of [Re 3 (µ-H) 3 (CO) 8 (CNCH 2 Ph)(µ 3 -η 2 :η 2 :η 2 -C 60 )], 20 in which the benzyl isocyanide ligand occupies an axial position. These results indicate that compounds 1-3 are isostructural with their C 60 analogues.…”

[60]Fullerene–Metal Cluster Complexes: Understanding Novel η1 and η2[6:5] Bonding Modes of Metallofullerenes

“…[35,38] One can easily assume that the bonding nature of η 1 and η 2 modes is quite different. It is worth noting that the η 1 and η 2 [6:5] bond strengths become high, as electron reductions proceed, with respect to the corresponding η 2 [6:6] bond strength.…”

“…The metallofullerene complexes with this relatively strong bonding mode exhibited remarkable thermal and electrochemical stabilities, uniquely suitable for various device applications, which is in contrast to other previously known η 2 -C 60 metal cluster complexes. [11] Park et al [35,38] demonstrated an interesting strong electronic communication between C 60 and metal cluster centers that can be readily fine-tuned by controlling the electronic properties of the attached ligands on the metal cluster center. Electrochemical studies of C 60 derivatives of Ir 4 and Rh 6 clusters have also revealed strong electronic interactions between C 60 cages, through the metal cluster spacers.…”

Transition Metal Complex Formation

“…Ru 3 (CO) 9 (µ 3 -η 2 :η 2 :η 2 -C 60 ) can be synthesized and isolated as red crystals by reacting two equiv. The rhenium-hydrido complex Re 3 (µ-H) 3 (CO) 11 (µ 3 -η 2 :η 2 :η 2 -C 60 ) (24) can be prepared by reaction of Re 3 (µ-H) 3 (CO) 11 (NCMe) with C 60 in refluxing chlorobenzene in 50% yield [69]. Chlorobenzene turned out to be the best solvent for the preparation of this fullerene-cluster complex [66].…”